Identification Of Organisms and Living Things
In thinking about identification of living things, the first question that comes to our mind is the need for identification of them. We know that we share the planet with at least 1.5 million other species. In order to communicate, retrieve store and accumulate information about our immediate neighbors like people , dogs, elephants, coconut trees and other plants, it is necessary to : (a). identify these organisms; (b) name them ; and (C) place these organisms into groups that reiect our current knowledge of their evolutionary relationships. As we know collectively these activities - identification, nomenclature and classification - make up the discipline of taxonomy .
Here we will focus only on identification
Identification could be defined as comparing an unknown one with that is already known; or at least recognize that the unknown doesn't have a known counterpart. So what does this mean ? Let's give an example. Suppose you didn't know that the bird which one of your friends is carrying is a parrot. How could you identify this creature ? The answer is simple in theory. We could compare the '' unknown bird '' to other ''known'' or "reference" or "type" birds until we find one that matches. If, we don't find a perfect match, we may have to follow the process of matching the unknown organism to known ones in some other ways.
How can we do that ?
A. Asking an expert or someone who knows.
Consult an individual who has spent his/ her life studying birds (ornithologist). This method usually provides a reliable and accurate answer because it is based on the wisdom and years of experience of a professional. "Experts" are typically found in botanical gardens, museums, herbaria, colleges , universities, etc.
B. Specimen Comparison.
In this case, we search through a field guide, museum or zoo for a bird that matches our mystery bird. If we were trying to identify a plant we could even search through the her barium. This can involve looking at pictures, actual specimens or descriptions. Although we may get lucky, this method is the least satisfactory because of the small probability that we will stumble upon the match.
C. Using a taxonomic key
A key is a device, which when properly constructed and used, enables a user to identify an organism. The most common and widely used type of key are dichotomous keys.
They consist of a series of paired statements, termed couplets, that describe some feature of the organism. The statements, or leads are in direct contrast. To use the key, begin with the first couplet and select the statement that best fits your specimen. this will direct you to another couplet and ultimately provide the identity of your specimen.
There are two types of dichotomous keys. They differ in the method by which the couplets are organized and how the user is directed to successive choices. They are Indented Keys and Bracketed Keys. At this point we are not discussing these two types and you will be studying them later.
A simple dichotomous key
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